System and device for keeping bone screws ready

ABSTRACT

A keeping-ready device for bone screws and a keeping-ready system comprising this keeping-ready device are described. The keeping-ready device has a surface, in which a plurality of orifices for accommodating the bone screws is provided. The keeping-ready device allows the bone screws to be kept ready countersunk in relation to the surface.

TECHNICAL FIELD

[0001] The invention relates to a device for keeping bone screws readyfor a surgical operation. The invention further relates to a system forkeeping bone screws ready, containing the keeping-ready device and aremoval instrument for removing kept-ready bone screws from thekeeping-ready device.

BACKGROUND OF THE INVENTION

[0002] Conventional keeping-ready devices for bone screws comprise apick-up sheet provided with a multiplicity of orifices for insertingbone screws. The diameters of these orifices are chosen in such a waythat on the one hand they are larger than the diameter of a screw shank,but on the other hand smaller than the diameter of a screw head. When abone screw is inserted into one of the orifices, with an underside ofthe screw head facing the pick-up sheet the bone screw consequentlycomes into contact with the surface of the sheet.

[0003] Bone screws kept ready in this way are picked up from the sheetduring a surgical operation by means of a suitable removal instrument,e.g. by a screw driver, and then screwed into a bone or into a fragmentof a bone.

[0004] The use of conventional keeping-ready devices allows bone screwsto be kept ready and picked up without their having to be taken into thehand. This is advantageous not only on grounds of hygiene, but also ofergonomics.

[0005] The object of the invention is to make available an improvedkeeping-ready device for bone screws and also a system comprising theimproved keeping-ready device.

SUMMARY OF THE INVENTION

[0006] According to the invention, to achieve this object a system forkeeping ready bone screws with a keeping-ready device for bone screwsand also a removal instrument for removing a bone screw from thekeeping-ready device and in particular for subsequently screwing thebone screw into a bone or into a fragment of a bone is proposed, whereinthe keeping-ready device according to the invention has a surface with aplurality of orifices for inserting the bone screws and thekeeping-ready device allows the inserted bone screws to be kept readycountersunk in relation to the surface. The removal instrument may bedimensioned in such a way that it can be inserted into the orifices forremoval of the bone screws arranged as countersunk.

[0007] The removal instrument can be designed as a screw driver blade,which could allow for a self-holding pick-up of a bone screw. Theself-holding pick-up can be produced, for example, by using magnetic ormagnetised materials for the removal instrument or by providing meansfor a non-positive connection between the removal instrument on the onehand and the head of the bone screw on the other hand.

[0008] The dimensions of the removal instrument and the orifices may bematched to one another in such a way that, e.g. cylindrically designeddelimitation walls of the orifices allow at least partial guiding of aninsertion movement of the removal instrument. Guiding of this kind isproduced in particular if the dimensions of the orifices are chosen aspartially only minimally, preferably 2 to 20%, larger than thedimensions of the end of the removal instrument to be inserted into theorifices. However, it is also conceivable to choose the dimensions ofthe orifices as substantially larger.

[0009] As well as the already mentioned keeping-ready device and theremoval instrument, the system for keeping ready bone screws accordingto the invention can comprise a plurality of bone screws, preferablywith different head shapes. The bone screws can have a different shankdiameter. Additionally the orifices of the keeping-ready device can bedifferently dimensioned.

[0010] As far as the orifices are concerned, there is the greatestvariety of modes of implementation available. The orifice cross-sectionis preferably chosen as circular. Other orifice cross-sections (e.g.elliptical, square, etc.) can, however, also be provided. Advantageouslythe shape of the orifice cross-section is matched to the cross-sectionof the removal end of a removal instrument.

[0011] According to a first version of the invention the orifices areconfigured as pocket holes, which are preferably constructed in akeeping-ready device designed as a solid block. With orifices of pockethole type the bone screws can be kept ready lying on the bottom of thepocket holes. The pocket holes can have different depths in order topick up bone screws of different length.

[0012] According to a second version of the invention the orificesprovided in a surface of the keeping-ready device are configured asthrough orifices. The through orifices can in this case be constructedin a thin (sheet) or thick first plate.

[0013] If the through orifices according to the second version of theinvention are constructed in a first plate, there can be a second plate,e.g. parallel to the first plate. The second plate is preferablydistanced from the first plate to such an extent that the bone screwsare kept ready by the keeping-ready device, e.g. with their heads ortips lying on the second plate.

[0014] In practice it has proved with conventional keeping-ready devicesthat slipping of the removal instrument from the screw head leads to akind of “trampoline effect” of the pick-up sheet and the screws canspring out of their orifices. To avoid this kind of trampoline effectthe ratio of area to thickness of the first plate is preferably chosenin such a way that the first plate has no or only slight springingproperties. The thickness of the first plate is preferably more thanapproximately 1 mm and in particular more than approximately 2 mm.Generally, said “trampoline effect” can be safely avoided at least ifthe delimitation walls of the orifices have an axial extension whichguarantees an adequate guiding function for the removal instrument to beinserted into the orifices.

[0015] According to a preferred configuration of the inventiondelimitation walls of the orifices in a region below the surface have areduction in inner diameter, which can act as a stop for a head of abone screw to be kept ready. The reduction in inner diameter can have aninner diameter which decreases from the surface of the keeping-readydevice at least partially constantly (e.g. conically) or in steps. Thecourse of the decrease in inner diameter should be matched to thedifferent head shapes of the usable bone screws.

[0016] The surface of the keeping-ready device advantageously has amultiplicity of more than 25 and in particular of more than 50 or 100orifices. The orifices can be arranged in the surface like a grid. Theratio of the total area of the surface including the orifices to thetotal area of the orifices can be between 1.5:1 and 5:1 and preferablybetween 2:1 and 4:1.

SHORT DESCRIPTION OF THE DRAWINGS

[0017] Further advantages and configurations of the invention emergefrom the following description of preferred embodiment examples and thefigures.

[0018]FIG. 1 shows a perspective view of a keeping-ready deviceaccording to the invention for bone screws, bone plates, etc.

[0019]FIG. 2 shows an aspect on to the keeping-ready device according toFIG. 1.

[0020]FIG. 3 shows a cross-section through a plate-shaped element of thekeeping-ready device according to FIGS. 1 and 2 in combination with aplurality of bone screws and removal instruments for the bone screws.

[0021]FIG. 4 shows an enlarged view of FIG. 3.

[0022]FIG. 5 shows an enlarged view of FIG. 4.

DESCRIPTION OF A PREFERRED EMBODIMENT

[0023] An embodiment of a system for keeping ready bone screws accordingto the invention is described below. The keeping-ready system accordingto the invention comprises in the example case different types of bonescrews and removal instruments. The invention could also be used incombination with other bone screws or removal instruments.

[0024] In FIG. 1 a perspective view of a keeping-ready device 10 forbone screws according to the invention is illustrated in the emptystate, i.e. without bone screws kept ready. The device 10 comprises akeeping-ready plate 12 and an accommodating frame 14 for the plate 12.By means of the frame 14 the plate 12 is positioned a few centimetresabove a support plane (e.g. an operating table) of the frame 14. Inaddition to an accommodating area for the plate 12, a multiplicity oforifices 18 for accommodating bone plates, surgical instruments, such asscrew drivers, etc., is constructed in a surface 16 of the frame 14.According to an alternative embodiment of the invention the device 10 iscut out of a single piece (e.g. a block of aluminium).

[0025]FIG. 2 shows an aspect on to the keeping-ready device 10 accordingto FIG. 1. In FIG. 2 it can be clearly seen that the plate 12 has asurface 20 in which a multiplicity of orifices 22 is arranged like agrid. In the case illustrated in FIG. 2 the ratio of the total area ofthe surface 20 including the area of the orifices 22 to the total areaof the orifices 22 is approximately 1:3.

[0026]FIG. 3 shows a section through the plate 12 according to FIG. 2 inthe region of eight orifices 22 located next to one another. In the viewaccording to FIG. 3 a plurality of different bone screws 24 which havebeen inserted into the orifices 22 is illustrated. Additionally, variousremoval instruments cooperating with the heads of the bone screws 24 areillustrated in the form of screw driver blades 26.

[0027] The heads of the bone screws are provided with a cross recessedstructure in each case and the screw driver blades 26 likewise have across recessed structure in each case on their ends cooperating with thebone screws. The cross recessed structures of the heads of the bonescrews 24 and the ends of the screw driver blades 26 are constructed insuch a way that the ends of the screw driver blades 26 can be broughtinto non-positive locking engagement into the cross recessed structuresof the heads of the bone screws 24. This enables self-holding pick-up ofthe bone screws 24 by means of the screw driver blades 26.

[0028] In FIG. 3 it can be clearly seen that the orifices 22 areconstructed as through orifices in the plate 12. The thickness of theplate 12 is approximately 2.5 mm. This ratio guarantees that the plate12 has no or only slight springing properties.

[0029] As can be seen from FIG. 3, the arrangement of the bone screws 24as countersunk in relation to the surface 20 of the plate 12 has theadvantage that the wall areas of the through orifices 22 above the headsof the bone screws 24 have a guiding function for the screw driverblades 26 when the screw driver blades 26 are inserted into the orifices22 for the purpose of removing the bone screws 24. This guiding functionis still reliably fulfilled if the diameter of the pick-up end of one ofthe screw driver blades 26 is considerably smaller than the maximumdiameter of the through orifice 22. In the case illustrated in FIG. 3this is due in particular to the fact that the orifice cross-section ofthe wall of the through orifice 22 is reduced in steps and therefore hasa centring function in the direction of the head of the bone screw to bepicked up for the two left screw driver blades in FIG. 3 with thesmaller dimensioned pick-up end.

[0030]FIG. 4 shows a detail enlargement of FIG. 3, wherein for the sakeof clarity not all the bone screws and screw driver blades have beenillustrated.

[0031] It can be seen from FIG. 4 that the delimitation walls of thethrough orifices 22 below the surface 20 of the plate 12 have in eachcase a reduction in inner diameter. More precisely, the inner diameterdecreases in each case in three steps. The inner diameter of the throughorifices 22 is largest immediately below the surface 20. A firstcylindrical wall area with the largest diameter runs into a secondcylindrical area of slightly smaller diameter. This second cylindricalarea runs into a third cylindrical area with a smaller diameter than thesecond cylindrical area. The third cylindrical area borders on anunderside 28 of the plate 12.

[0032] At the transition from the first to the second cylindrical areathe wall of the through orifice 22 has a step in the form of a firstcircular-ring-shaped stop 30 and at the transition from the secondcylindrical area to the third cylindrical area a further step in theform of a second circular-ring-shaped stop 32.

[0033] The step-shaped decrease in the inner diameter of the walls ofthe through orifices 22 illustrated in FIG. 4 allows secure picking upof bone screws with different head diameters. As a function of the headdiameter of the bone screw to be picked up, when it is inserted into thethrough orifice 22 it comes into contact either with the upper stop 30in FIG. 4, or with the lower stop 32 in FIG. 4. If one looks at FIG. 3,it can be clearly seen that the two left bone screws in FIG. 3 withtheir heads have come into contact with the lower stop (referencenumeral 32 in FIG. 4) and the remaining bone screws with their headsinto contact with the upper stop in FIG. 3 (reference numeral 30 in FIG.4).

[0034]FIG. 5 shows a detail enlargement from FIG. 4 in the area of theleft bone screw 24 in FIG. 4. For the sake of clarity, in FIG. 5 theright bone screw in FIG. 4 and also the screw driver blades 26 have beenleft out.

[0035] As can be seen from FIG. 5, the bone screw 24 has a screw head 38with a head thread 40. The screw head 38 is provided on its radiallyouter end with a bezel 42, which cooperates in positive locking with theupper stop 30, running crosswise in relation to the surface 20 of theplate 12. The cooperation of the bezel 42 of the head 38 of the bonescrew 24 with the conically constructed upper stop 30 effectsself-centring of an inserted bone screw 24.

[0036] The above-described embodiment of the invention is intended to bean example of the present invention, and alterations and modificationsmay be effected thereto, by those of ordinary skilled in the art,without departing from the scope of the invention which is defined bythe claims appended hereto.

1. A system for keeping ready bone screws comprising a keeping-readydevice for bone screws, wherein the keeping-ready device has a surfacewith a plurality of orifices for inserting the bone screws and thekeeping-ready device allows the inserted bone screws to be kept readycountersunk in relation to the surface; and a removal instrument forremoving a kept-ready bone screw from the keeping-ready device, whereinthe removal instrument is dimensioned such that it is insertable intoone of the orifices for removal of a kept-ready bone screw.
 2. Thesystem for keeping ready bone screws according to claim 1, wherein theremoval instrument and the orifices are dimensioned such thatdelimitation walls of the orifices allow at least partial guiding of aninsertion movement of the removal instrument.
 3. The system for keepingready bone screws according to claim 1, further comprising a pluralityof bone screws, with different head shapes.
 4. A keeping-ready devicefor bone screws, comprising a surface in which a plurality of orificesfor inserting the bone screws is provided, wherein the keeping-readydevice allows the inserted bone screws to be kept ready countersunk inrelation to the surface.
 5. The keeping-ready device according to claim4, wherein the orifices have delimitation walls which act as a guide fora removal instrument for the bone screws that is to be inserted into oneof the orifices.
 6. The keeping-ready device according to claim 4,wherein the orifices are configured as pocket holes.
 7. Thekeeping-ready device according to claim 6, wherein the pocket holes areconstructed in such a way that the bone screws are kept ready lying onthe bottom of the pocket holes.
 8. The keeping-ready device according toclaim 4, wherein the orifices are configured as through orifices.
 9. Thekeeping-ready device according to claim 8, further comprising a firstplate in which the through orifices are constructed.
 10. Thekeeping-ready device according to claim 9, further comprising a secondplate which is distanced from the first plate to such an extent that thebone screws are kept ready lying on the second plate.
 11. Thekeeping-ready device according to claim 9, wherein the ratio of area tothickness of the first plate is chosen in such a way that the firstplate has no or only slight springing properties.
 12. The keeping-readydevice according to claim 4 or 5, wherein the delimitation walls of theorifices in a region below the surface have a reduction in innerdiameter.
 13. The keeping-ready device according to claim 12, whereinthe reduction in inner diameter has an inner diameter at least partiallygradually decreasing from the surface.
 14. The keeping-ready deviceaccording to claim 13, wherein the inner diameter decreases continuouslyor in steps from the surface.
 15. The keeping-ready device according toclaim 12, wherein the reduction in inner diameter acts as a stop for ahead of a bone screw to be kept ready.
 16. The keeping-ready deviceaccording to claim 4, wherein the orifices are arranged in the surfacelike a grid.
 17. A device for keeping bone screws ready, the bone screwshaving bone screw heads and the device comprising a surface in whichorifices are provided for keeping-ready the bone screws with countersunkbone screw heads in relation to the surface, the orifices having wallsthat act as a guide for a removal instrument for the bone screws whenthe removal instrument is inserted into one of the orifices.
 18. Thedevice according to claim 17, wherein the orifices include portions ofreduced inner diameter that act as stops for the bone screw heads.
 19. Adevice for keeping bone screws ready, the bone screws having bone screwheads and the device comprising a surface in which a plurality oforifices for inserting the bone screws is provided, wherein the orificeshave portions of a reduced inner diameter for cooperating with bonescrew heads and wherein the portions of reduced inner diameter areplaced such that the bone screw heads are kept ready countersunk inrelation to the surface.
 20. The device according to claim 19, whereinthe orifices include portions of a widened inner diameter preceding theportions of reduced inner diameter in a insertion direction and whereinthe portions of widened diameter constitute a guide for a removalinstrument that is to be inserted into the orifices for removing thebone screws.